The present invention relates generally to wireless communication systems and, in particular, to data transfer over such wireless communication systems.
Due to the nature of transmitting facsimile data within a communication system, often times it is necessary to insert blank lines at the top of a page in order to keep the receiving facsimile machine from disconnecting. More particularly, situations (such as the necessity to retransmit data due to high bit error rates (BERs), delays caused by the facsimile protocol, and delays caused by demodulation, transmission, and remodulation of signals) can cause unacceptable delays when transmitting a facsimile, causing a page start timer to expire. Prior-art procedures addressing this situation have prevented the receiving facsimile machine from disconnecting by periodically sending the receiving facsimile machine a series of blank scan lines when the subscriber equipment detects an unacceptable delay in reception. The result is that the receiving facsimile machine recognizes the blank lines as part of the facsimile transmission, and remains connected. Such a prior-art procedure of facsimile transmission is described in Telecommunications Industry Association/Electronics Industry Association/Interim Standard 707-A.7 (EIA/TIA/IS-707-A.7) sections 5.1.2 and 6.2.2. In accordance with EIA/TIA/IS-707-A.7, the insertion of each blank line requires the removal of scan lines from the actual facsimile to maintain a fixed number of lines per page. As a result, actual image scan lines (i.e., non-blank lines) may be discarded from the page to maintain a fixed number of lines per page. Therefore, a need exists for a method and apparatus for data transfer within a communication system that allows for a receiving facsimile machine to remain connected during long periods of delay, while preserving the actual image scan lines transmitted.